Antidepressant azaheterocyclymethyl derivatives of 7,8-dihydro-3H-6,9-dioxa-1,3-diazacyclopenta[a]naphthalene

ABSTRACT

Compounds of the formula: 
                 
 
are useful for the treatment of depression and other diseases such as obsessive compulsive disorder, panic attacks, generalized anxiety disorder, social anxiety disorder, sexual dysfunction, eating disorders, obesity, addictive disorders caused by ethanol or cocaine abuse and related illnesses.

This is a continuation of application Ser. No. 10/128,762, filed on Apr. 23, 2002, now U.S. Pat. No. 6,573,283, which claims the benefit of provisional application Ser. No. 60/286,579, filed on Apr. 26, 2001, the entire disclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

Major depression is a serious health problem affecting more than 5% of the population, with a life-time prevalence of 15-20%.

Selective serotonin reuptake inhibitors have produced significant success in treating depression and related illnesses and have become among the most prescribed drugs. They nonetheless have a slow onset of action, often taking several weeks to produce their full therapeutic effect. Furthermore, they are effective in fewer than two-thirds of patients.

Serotonin selective reuptake inhibitors (SSRIs) are well known for the treatment of depression and other conditions. SSRIs work by blocking the neuronal reuptake of serotonin, thereby increasing the concentration of serotonin in the synaptic space, and thus increasing the activation of postsynaptic serotonin receptors.

However, although a single dose of an SSRI can inhibit the neuronal serotonin transporter which would be expected to increase synaptic serotonin, long-term treatment is required before clinical improvement is achieved.

It has been suggested that the SSRIs increase the serotonin levels in the vicinity of the serotonergic cell bodies and that the excess serotonin activates somatodendritic autoreceptors, 5-HT_(1A) receptors, causing a decrease in serotonin release in major forebrain areas. This negative feedback limits the increment of synaptic serotonin that can be induced by antidepressants.

A 5-HT_(1A) antagonist would limit the negative feedback and should improve the efficacy of the serotonin reuptake mechanism. (Perez, V., et al., The Lancet, 349:1594-1597 (1997)). Such a combination therapy would be expected to speed up the effect of the serotonin reuptake inhibitor.

Thus, it is highly desirable to provide improved compounds which both inhibit serotonin reuptake and which are antagonists of the 5-HT_(1A) receptor.

DESCRIPTION OF THE INVENTION

In accordance with this invention, there is provided a group of novel compounds of the formula:

wherein

-   -   R¹, R², R³, R⁴, R⁵ and R⁸ are independently hydrogen, halo,         cyano, carboxamido, carboalkoxy of two to six carbon atoms,         trifluoromethyl, pentafluoroethyl, alkyl of 1 to 6 carbon atoms,         alkoxy of 1 to 6 carbon atoms, alkanoyloxy of 2 to 6 carbon         atoms, amino, mono- or di-alkylamino in which each alkyl group         has 1 to 6 carbon atoms, alkanamido of 2 to 6 carbon atoms, or         alkanesulfonamido of 1 to 6 carbon atoms;     -   R⁶ and R⁷ are, independently, hydrogen or alkyl of 1 to 6 carbon         atoms;     -   A dotted line represents an optional double bond;     -   Z is CR⁸ or N; and     -   n is an integer 0, 1 or 2;     -   or a pharmaceutically acceptable salt thereof.

In some preferred embodiments of the present invention, R¹ is hydrogen, halo, cyano, trifluoromethyl, alkyl of one to six carbon atoms or alkoxy of one to six carbon atoms, and more preferably R¹ is hydrogen.

In other embodiments of the invention R² is hydrogen, halo, trifluoromethyl, pentafluoroethyl, alkyl of one to six carbon atoms, alkoxy of one to six carbon atoms, amino, mono- or di-alkylamino in which each alkyl group has one to six carbon atoms. R² is more preferably hydrogen, trifluoromethyl, pentafluoroethyl or lower alkyl.

In still other embodiments of the invention R³, R⁴ and R⁵ are independently selected from hydrogen, halo, cyano, carboxamido, alkyl of one to six carbon atoms, and alkoxy of one to six carbon atoms. R³, R⁴ and R⁵ are more preferably independently selected from hydrogen, cyano and halogen, and most preferably hydrogen or halogen.

Where Z is CR⁸, R⁸ is preferably hydrogen, halo, cyano, carboxamido, alkyl of one to six carbon atoms, or alkoxy of one to six carbon atoms, more preferably hydrogen, cyano or halogen and most preferably hydrogen or halogen.

R⁶ is preferably hydrogen in some embodiments of the invention.

R⁷ is preferably hydrogen or lower alkyl in other embodiments of the invention.

In other preferred embodiments n is preferably 0 or 1 and most preferably 0.

The optional double bond is preferably present in still other preferred embodiments of the invention.

Of the compounds of Formula I, still more preferred are compounds in which R¹ is hydrogen, halogen, cyano, trifluoromethyl, alkyl of one to six carbon atoms, or alkoxy of one to six carbon atoms; R² is hydrogen, halogen, trifluoromethyl, pentafluoroethyl, alkyl of one to six carbon atoms, alkoxy of one to six carbon atoms, amino, mono- or di-alkylamino in which each alkyl group has one to six carbon atoms; R³, R⁴ and R⁵ are independently selected from hydrogen, halogen, cyano, carboxamido, alkyl of one to six carbon atoms, and alkoxy of one to six carbon atoms; n is an integer 0 or 1.

Still more preferred are those compounds in which R¹ is hydrogen, halogen, cyano, trifluoromethyl, alkyl of one to six carbon atoms, or alkoxy of one to six carbon atoms; R² is hydrogen, trifluoromethyl, pentafluoroethyl, or alkyl of one to six carbon atoms, R³, R⁴ and R⁵ are independently selected from hydrogen, halogen and cyano, R⁶ and R⁷ are hydrogen, n is 0 and the dotted line represents a double bond.

In still more preferred embodiments of the present invention R¹ is hydrogen, R² is trifluoromethyl, pentafluoroethyl, or lower alkyl, R³, R⁴ and R⁵ are independently selected from hydrogen and halogen, R⁶ is hydrogen, R⁷ is hydrogen or lower alkyl, Z is CR⁸, R⁸ is hydrogen or halo, n is 0, and the optional double bond is present.

This invention relates to both the R and S stereoisomers of the 8-aminomethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene, as well as to mixtures of the R and S stereoisomers. Throughout this application, the name of the product of this invention, where the absolute configuration of the 8-aminomethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene is not indicated, is intended to embrace the individual R and S enantiomers as well as mixtures of the two. In some preferred embodiments of the present invention the S isomer is preferred.

Where a stereoisomer is preferred, it may in some embodiments be provided substantially free of the corresponding enantiomer. Thus, an enantiomer substantially free of the corresponding enantiomer refers to a compound which is isolated or separated via separation techniques or prepared free of the corresponding enantiomer. Substantially free, as used herein means that the compound is made up of a significantly greater proportion of one stereoisomer. In preferred embodiments the compound is made up of at least about 90% by weight of a preferred stereoisomer. In other embodiments of the invention, the compound is made up of at least about 99% by weight of a preferred stereoisomer. Preferred stereoisomers may be isolated from racemic mixtures by any method known to those skilled in the art, including high performance liquid chromatography (HPLC) and the formation and crystallization of chiral salts or by methods described herein. See, for example, Jacques, et al., Enantiomers, Racemates and Resolutions (Wiley Interscience, New York, 1981); Wilen, S. H., et al., Tetrahedron 33:2725 (1977); Eliel, E. L. Stereochemistry of Carbon Compounds (McGraw-Hill, NY, 1962); Wilen, S. H. Tables of Resolving Agents and Optical Resolutions p. 268 (E. L. Eliel, Ed., Univ. of Notre Dame Press, Notre Dame, Ind. 1972).

It is further recognized that tautomers of the claimed compounds may exist, for instance, when R⁷ is hydrogen the imidazole may exist in either of two tautomeric forms. The claims in this application, either for the title compounds or intermediates, are intended to embrace both of the tautomers, as well as mixtures of the two.

Alkyl as used herein refers to an aliphatic hydrocarbon chain and includes straight and branched chains such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neo-pentyl, n-hexyl, and isohexyl. Lower alkyl refers to alkyl having 1 to 3 carbon atoms.

Alkanamido as used herein refers to the group R—C(═O)—NH— where R is an alkyl group of 1 to 5 carbon atoms.

Alkanoyloxy as used herein refers to the group R—C(═O)—O— where R is an alkyl group of 1 to 5 carbon atoms.

Alkanesulfonamido as used herein refers to the group R—S(O)₂—NH— where R is an alkyl group of 1 to 6 carbon atoms.

Alkoxy as used herein refers to the group R—O— where R is an alkyl group of 1 to 6 carbon atoms.

Carboxamido as used herein refers to the group —CO—NH₂.

Carboalkoxy as used herein refers to the group R—O—C(═O)— where R is an alkyl group of 1 to 5 carbon atoms.

Halogen (or halo) as used herein refers to chlorine, bromine, fluorine and iodine.

Pharmaceutically acceptable salts are those derived from such organic and inorganic acids as: acetic, lactic, citric, cinnamic, tartaric, succinic, fumaric, maleic, malonic, mandelic, malic, oxalic, propionic, hydrochloric, hydrobromic, phosphoric, nitric, sulfuric, glycolic, pyruvic, methanesulfonic, ethanesulfonic, toluenesulfonic, salicylic, benzoic, and similarly known acceptable acids.

Specific compounds of Formula I include:

8-[4-(5-fluoro-1H-indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2-trifluoromethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene;

8-[4-(1H-indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2-trifluoromethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene;

8-[4-(6-fluoro-1H-indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2-trifluoromethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene;

8-[4-(1H-indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2-methyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene;

8-[4-(1H-indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-1,2-dimethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene;

8-[4-(1H-indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2-ethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene;

8-[4-(7-Fluoro-1H-indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2-trifluoromethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene; and

8-[4-(1H-Indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2-pentafluoroethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene; or a pharmaceutically acceptable salt thereof.

The 8-azaheterocyclylmethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diazacyclo-penta[a]-naphthalenes of the invention are prepared as illustrated below using certain novel intermediates. Specifically, the appropriately substituted nitroguaiacol (1) is alkylated with allyl bromide in the presence of a suitable base such as sodium hydride (2) and then demethylated by a reagent such as sodium hydroxide. The resulting 4-nitro-2-allyloxyphenol (3) is then alkylated with glycidyl tosylate or an epihalohydrin in the presence of a base such as sodium hydride to produce (4) and heated in a high boiling solvent such as mesitylene or xylene to effect both rearrangement of the allyl group and cyclization of the dioxan ring. The resulting primary alcohol (5) is converted to the tosylate (6) by reaction with p-toluenesulfonyl chloride in the presence of a tertiary amine or pyridine, or alternatively to a halide by reaction with carbon tetrabromide or carbon tetrachloride in combination with triphenylphosphine. The allyl side chain is then isomerized by treatment with catalytic bis-acetonitrile

palladium (II) chloride in refluxing methylene chloride or benzene and cleaved to the corresponding o-nitrobenzaldehyde by treatment with ozone followed by diisopropylethylamine or by catalytic osmium tetroxide in the presence of sodium periodate. The aldehyde is oxidized to the o-nitrobenzoic acid (7) by a suitable oxidant such as chromium trioxide (Jones' oxidation) or sodium chlorite and the acid converted to the o-nitroaniline with diphenylphosphoryl azide (DPPA) in the presence of a tertiary base such as diisopropylethylamine (Curtius reaction). Reduction of the resulting nitroaniline to the diamine (8) with hydrogen and palladium on carbon and cyclization by treatment at reflux with the appropriate carboxylic acid gives the novel intermediate 7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene (9).

Refluxing the diamine dihydrochloride in higher boiling carboxylic acids occasionally causes replacement of a tosylate group with a chloride. Replacement of the tosylate or halide with the appropriately substituted azaheterocycle in some high boiling solvent such as dimethyl sulfoxide gives the title compounds of Formula I in which R² is hydrogen or alkyl.

Treatment of the diamine (8) described above with cyanogen bromide or chloride or a suitably substituted carbamoyl chloride leads to compounds of the invention in which R² is amino. Treatment of the diamine (8) with carbonyl diimidazole gives the imidazolone which leads to compounds of the invention in which R² is halogen via treatment with an inorganic anhydride such as phosphoryl chloride or bromide, or to compounds of the invention in which R² is alkoxy by treatment with the appropriate alkylating agent. Replacement of the tosylate with the appropriately substituted azaheterocycle as above gives the title compounds of the invention.

The o-nitrobenzaldehyde used in the Jones' oxidation described above may be alternatively prepared as shown in Scheme II. The appropriate mono-allylated catechol (10) is elaborated with glycidyl tosylate as described above to produce (11) and rearranged in refluxing mesitylene. Cyclization to the benzodioxan methanol is effected by treatment with sodium bicarbonate in ethanol and the alcohol (12) is converted to the tosylate or halide as described above. After rearrangement of the double bond by treatment with catalytic bis-acetonitrile palladium (II) chloride in refluxing methylene chloride to produce (13) and cleavage with ozone or osmium tetroxide/sodium periodate as described above to produce (14), the resulting aldehyde is regioselectively nitrated with a combination of nitric acid and tin (IV) chloride to produce (15).

Compounds of the invention in which R² is trifluoromethyl may also be conveniently prepared from the nitroaniline described above by the procedure illustrated in Scheme III. The nitroaniline (15) is treated with trifluoroacetic anhydride in the presence of a suitable tertiary base such as diisopropylethylamine to yield the o-nitrophenyl trifluoroacetamide (16). This intermediate is reduced to the o-anilino tifluoroacetmide (17) by treatment with hydrogen over palladium on carbon and cyclized to the trifluoromethylimidazole (19) in refluxing trifluoroacetic acid. Alternatively, the o-nitrophenyl trifluoroacetamide (16) may be alkylated to produce (18) by treatment with an alkyl halide or tosylate in the presence of a base such as potassium carbonate. Reduction of the nitro group as before and cyclization in refluxing trifluoroacetic acid leads to trifluoromethylimidazoles in which R⁷ is alkyl (19). Removal of the trifluoroacetyl group after alkylation by treatment with potassium carbonate in methanol to produce (20), followed by reduction of the nitro group with hydrogen over palladium on carbon as above and cyclization by refluxing with the appropriate carboxylic acid leads to novel imidazoles of Formula II in which R² and R⁷ are alkyl (21). Replacement of the tosylate with the appropriately substituted azaheterocycle as above gives the title compounds of Formula I.

The guaiacols, catechols and azaheterocycles appropriate to the above chemistry are known compounds or can be prepared by one schooled in the art. The compounds of the invention may be resolved into their enantiomers by conventional methods or, preferably, the individual enantiomers may be prepared directly by substitution of (2R)-(−)-glycidyl 3-nitrobenzenesulfonate or tosylate (for the S benzodioxan methanamine) or (2S)-(+)-glycidyl 3-nitrobenzenesulfonate or tosylate (for the R enantiomer) in place of epihalohydrin or racemic glycidyl tosylate in the procedures above.

A protocol similar to that used by Cheetham et. al. (Neuropharmacol. 32:737, 1993) was used to determine the affinity of the compounds of the invention for the serotonin transporter. The compound's ability to displace ³H-paroxetine from male rat frontal cortical membranes was determined using a Tom Tech filtration device to separate bound from free ³H-paroxetine and a Wallac 1205 Beta Plate® counter to quantitate bound radioactivity. K_(i)'s thus determined for standard clinical antidepressants are 1.96 nM for fluoxetine, 14.2 nM for imipramine and 67.6 nM for zimelidine. A strong correlation has been found between ³H-paroxetine binding in rat frontal cortex and ³H-serotonin uptake inhibition.

High affinity for the serotonin 5-HT_(1A) receptor was established by testing the claimed compound's ability to displace [³H] 8-OHDPAT (dipropylaminotetralin) from the 5-HT_(1A) serotonin receptor following a modification of the procedure of Hall et al., J. Neurochem. 44, 1685 (1985) which utilizes CHO cells stably transfected with human 5-HT_(1A) receptors. The 5-HT_(1A) affinities for the compounds of the invention are reported below as K_(i)'s.

Antagonist activity at 5-HT_(1A) receptors was established by using a ³⁵S-GTPγS binding assay similar to that used by Lazareno and Birdsall (Br. J. Pharmacol. 109: 1120, 1993), in which the test compound's ability to affect the binding of ³⁵S-GTPγS to membranes containing cloned human 5-HT_(1A) receptors was determined. Agonists produce an increase in binding whereas antagonists produce no increase but rather reverse the effects of the standard agonist 8-OHDPAT. The test compound's maximum inhibitory effect is represented as the I_(max), while its potency is defined by the IC₅₀.

The results of the three standard experimental test procedures described in the preceding three paragraphs were as follows:

5-HT Transporter 5-HT_(1A) 5-HT_(1A) Function Affinity Receptor Affinity IC₅₀ (nM) Compound KI (nM) KI (nM) (I_(max)) Example 1 1.04 3.07 93.5 (100) Example 2 1.05 1.76 29.0 (82.5) Example 3 1.12 2.67 22.0 (66.5) Example 4 0.41 1.58 10.0 (100) Example 5 2.00 52.04 6515.0 (100) Example 6 0.42 1.34 36.0 (35.0) Example 7 0.69 0.81 27.4 (89.1) Example 8 1.25 1.88 43.6 (91.1)

Like the antidepressants fluoxetine, paroxetine and sertraline, the compounds of this invention have the ability to potently block the reuptake of the brain neurotransmitter serotonin. They are thus useful for the treatment of depression and other diseases commonly treated by the administration of serotonin selective reuptake inhibitor (SSRI) antidepressants. Moreover, the compounds of this invention have potent affinity for and antagonist activity at brain 5-HT_(1A) serotonin receptors. Recent clinical trials employing drug mixtures (eg, fluoxetine and pindolol) have demonstrated a more rapid onset of antidepressant efficacy for a treatment combining SSRI activity and 5-HT_(1A) antagonism (Blier and Bergeron, 1995; F. Artigas et. al., 1996; M. B. Tome et. al., 1997). The compounds of the invention are thus exceedingly interesting and useful for treating depressive illnesses.

Hence, the compounds of this invention are combined serotonin reuptake inhibitors/5-HT_(1A) antagonists and are useful for the treatment of conditions related to or affected by the reuptake of serotonin and by the serotonin 1A receptor, such as depression (including but not limited to major depressive disorder, childhood depression and dysthymia), anxiety, panic disorder, post-traumatic stress disorder, premenstrual dysphoric disorder (also known as pre-menstrual syndrome), attention deficit disorder (with and without hyperactivity), obsessive compulsive disorder (including trichotillomania), social anxiety disorder, generalized anxiety disorder, obesity, eating disorders such as anorexia nervosa, bulimia nervosa, vasomotor flushing, cocaine and alcohol addiction, sexual dysfunction (including premature ejaculation), and related illnesses.

Thus the present invention provides methods of treating, preventing, inhibiting or alleviating each of the maladies listed above in a mammal, preferably in a human, the methods comprising providing a pharmaceutically effective amount of a compound of this invention to the mammal in need thereof.

Also encompassed by the present invention are pharmaceutical compositions for treating or controlling disease states or conditions of the central nervous system comprising at least one compound of Formula I, mixtures thereof, and or pharmaceutical salts thereof, and a pharmaceutically acceptable carrier therefore. Such compositions are prepared in accordance with acceptable pharmaceutical procedures, such as described in Remingtons Pharmaceutical Sciences, 17th edition, ed. Alfonoso R. Gennaro, Mack Publishing Company, Easton, Pa. (1985). Pharmaceutically acceptable carriers are those that are compatible with the other ingredients in the formulation and biologically acceptable.

The compounds of this invention may be administered orally or parenterally, neat or in combination with conventional pharmaceutical carriers. Applicable solid carriers can include one or more substances which may also act as flavoring agents, lubricants, solubilizers, suspending agents, fillers, glidants, compression aids, binders or tablet-disintegrating agents or an encapsulating material. In powders, the carrier is a finely divided solid which is in admixture with the finely divided active ingredient. In tablets, the active ingredient is mixed with a carrier having the necessary compression properties in suitable proportions and compacted in the shape and size desired. The powders and tablets preferably contain up to 99% of the active ingredient. Suitable solid carriers include, for example, calcium phosphate, magnesium stearate, talc, sugars, lactose, dextrin, starch, gelatin, cellulose, methyl cellulose, sodium carboxymethyl cellulose, polyvinylpyrrolidine, low melting waxes and ion exchange resins.

Liquid carriers may be used in preparing solutions, suspensions, emulsions, syrups and elixirs. The active ingredient of this invention can be dissolved or suspended in a pharmaceutically acceptable liquid carrier such as water, an organic solvent, a mixture of both or pharmaceutically acceptable oils or fat. The liquid carrier can contain other suitable pharmaceutical additives such as solubilizers, emulsifiers, buffers, preservatives, sweeteners, flavoring agents, suspending agents, thickening agents, colors, viscosity regulators, stabilizers or osmo-regulators. Suitable examples of liquid carriers for oral and parenteral administration include water (particularly containing additives as above e.g. cellulose derivatives, preferably sodium carboxymethyl cellulose solution), alcohols (including monohydric alcohols and polyhydric alcohols e.g. glycols) and their derivatives, and oils (e.g. fractionated coconut oil and arachis oil). For parenteral administration the carrier can also be an oily ester such as ethyl oleate and isopropyl myristate. Sterile liquid carriers are used in sterile liquid form compositions for parenteral administration.

Liquid pharmaceutical compositions which are sterile solutions or suspensions can be utilized by, for example, intramuscular, intraperitoneal or subcutaneous injection. Sterile solutions can also be administered intravenously. Oral administration may be either liquid or solid composition form.

Preferably the pharmaceutical composition is in unit dosage form, e.g. as tablets, capsules, powders, solutions, suspensions, emulsions, granules, or suppositories. In such form, the composition is sub-divided in unit dose containing appropriate quantities of the active ingredient; the unit dosage forms can be packaged compositions, for example packeted powders, vials, ampoules, prefilled syringes or sachets containing liquids. The unit dosage form can be, for example, a capsule or tablet itself, or it can be the appropriate number of any such compositions in package form.

The amount provided to a patient will vary depending upon what is being administered, the purpose of the administration, such as prophylaxis or therapy, and the state of the patient, the manner of administration, and the like. In therapeutic applications, compounds of the present invention are provided to a patient already suffering from a disease in an amount sufficient to cure or at least partially ameliorate the symptoms of the disease and its complications. An amount adequate to accomplish this is defined as a “therapeutically effective amount.” The dosage to be used in the treatment of a specific case must be subjectively determined by the attending physician. The variables involved include the specific condition and the size, age and response pattern of the patient. Generally, a starting dose is about 5 mg per day with gradual increase in the daily dose to about 150 mg per day, to provide the desired dosage level in the human.

Provide, as used herein, means either directly administering a compound or composition of the present invention, or administering a prodrug, derivative or analog which will form an equivalent amount of the active compound or substance within the body.

The present invention includes prodrugs of compounds of Formula I. “Prodrug”, as used herein means a compound which is convertible in vivo by metabolic means (e.g. by hydrolysis) to a compound of Formula I. Various forms of prodrugs are known in the art, for example, as discussed in Bundgaard, (ed.), Design of Prodrugs, Elsevier (1985); Widder, et al. (ed.), Methods in Enzymology, vol. 4, Academic Press (1985); Krogsgaard-Larsen, et al., (ed). “Design and Application of Prodrugs, Textbook of Drug Design and Development, Chapter 5, 113-191 (1991), Bundgaard, et al., Journal of Drug Deliver Reviews, 8:1-38(1992), Bundgaard, J. of Pharmaceutical Sciences, 77:285 et seq. (1988); and Higuchi and Stella (eds.) Prodrugs as Novel Drug Delivery Systems, American Chemical Society (1975).

The following examples illustrate the production of representative compounds of this invention.

INTERMEDIATE 1 3-Allyloxy-4-methoxynitrobenzene

97.5 g (0.51 mole) of the sodium salt of 5-nitroguaiacol was dissolved in one liter of N,N-dimethylformamide and 1.5 equivalents of allyl bromide added. The reaction was heated to 65° C. for two hours, after which time much of the dark color had discharged and tlc (1:1 methylene chloride/hexane) indicated loss of starting material. The solvent was concentrated in vacuum and the residue washed with water. The product was isolated by filtration and dried in a vacuum. This gave 112 g of pale yellow solid. A sample recrystallized from methanol, gave m.p. 93-94° C.

INTERMEDIATE 2 2-Allyloxy-4-nitrophenol

To one liter of dimethyl sulfoxide was added 750 mL of 2 N aqueous sodium hydroxide and the mixture was heated to 65° C. The pale yellow solid 3-allyloxy-4-methoxynitrobenzene prepared above was added in portions over a 30 minute period and then the temperature was raised to 95° C. and maintained for 3 hours, after which time the starting material had been consumed. The mixture was allowed to cool and poured into a mixture of 1 L ice and 1 L 2 N HCl. 73 Grams of crude but homogeneous (by tlc 1:1 methylene chloride/hexane) desired product was isolated as a light brown solid by filtration. This material was subsequently dissolved in 1:1 hexane/methylene chloride and filtered through silica gel to give 68 g of pale yellow solid, which, when recrystallized from ethyl/acetate/hexane, gave m.p. 61-62° C. The aqueous mother liquors from the initial crystallization above were extracted with 2 L of ethyl acetate. This was dried over sodium sulfate, filtered and evaporated to a dark oil. Column chromatography on silica with 1:1 methylene chloride/hexane gave an additional 12 g of the title compound as a yellow solid. Elution with 2% methanol in chloroform gave 12 g of a dark oil which slowly crystallized in vacuum. This proved to be the Claisen product, 3-allyl-4-nitrocatechol.

INTERMEDIATE 3 2-(2-Allyloxy-4-nitrophenoxymethyl)-oxirane

20 g (0.50 mole) of 60% NaH/mineral oil was placed in a two liter flask and washed with 500 mL of hexane. 1 L of DMF was added, followed by 77 g (0.40 mole) of the 2-allyloxy-4-nitrophenol prepared in the previous step. Addition of the phenol was performed in portions under argon. After stirring the mixture for 30 minutes at room temperature under argon, 108 g (0.48 moles) of (R)-glycidyl tosylate was added and the mixture heated at 70-75° C. under nitrogen overnight. Upon cooling, the N,N-dimethylformamide was removed in vacuum and replaced with one liter of methylene chloride. This was washed with 500 mL portions of 2 N HCl, saturated sodium bicarbonate and saturated brine and dried over sodium sulfate. The mixture was filtered, concentrated to an oil in vacuum and column chromatographed on silica gel using 1:1 hexane/methylene chloride as eluant. This gave 43 g of product contaminated with traces of the two starting materials, followed by 21 g of pure product as a pale yellow solid. The impure material was recrystallized from 1.2 L of 10% ethyl acetate/hexane to give 34 g of pure (homogeneous on silica gel tlc with 1:1 hexane/methylene chloride) (R)-2-(2-allyloxy-4-nitrophenoxymethyl)-oxirane (m.p. 64° C.).

Elemental Analysis for: C₁₂H₁₃NO₅; Calc'd: C, 57.37; H, 5.21; N, 5.58. Found: C, 57.50; H, 5.21; N, 5.43.

INTERMEDIATE 4 (8-Allyl-7-nitro-2,3-dihydro-benzo(1,4)dioxin-2-yl)-methanol

(R)-2-(2-Allyloxy-4-nitrophenoxymethyl)-oxirane (20 g, 80 mmole) prepared as above was heated at 155° C. in mesitylene for 24 hours under nitrogen. Filtration of the black solid which formed gave 1.5 g of very polar material. Evaporation of the solvent in vacuum followed by column chromatography on silica gel with methylene chloride as eluant gave 10 g of recovered starting material and 7.5 g of the desired rearranged (S)-(8-allyl-7-nitro-2,3-dihydro-benzo(1,4)dioxin-2-yl)-methanol, which slowly crystallized on standing in vacuum (m.p. 67° C.). The yield based on recovered starting material is 75%.

Elemental Analysis for: C₁₂H₁₃NO₅; Calc'd: C, 57.37; H, 5.21; N, 5.58. Found: C, 57.26; H, 5.20; N, 5.35.

INTERMEDIATE 5 Toluene-4-sulfonic acid 8-allyl-7-nitro-2,3-dihydro-benzo(1,4)dioxin-2-ylmethyl ester

9.55 g (38.0 mmole) of (S)-(8-allyl-7-nitro-2,3-dihydro-benzo(1,4)dioxin-2-yl)-methanol was dissolved in 465 mL of pyridine, 29.0 g (152 mmole) of p-toluenesulfonyl chloride was added and the mixture stirred at room temperature under nitrogen overnight. Water was then added to quench the excess tosyl chloride and the solvent was removed in vacuum and replaced with methylene chloride. This solution was washed with 2 N HCl, with saturated sodium bicarbonate, and with saturated brine, and dried over magnesium sulfate. Filtration, evaporation in vacuum and column chromatography on silica gel with 1:1 hexane/methylene chloride as eluant gave 12.6 g (92%) of toluene-4-sulfonic acid (R)-allyl-7-nitro-2,3-benzo(1,4)dioxin-2-ylmethyl ester, which slowly crystallized to a tan solid (m.p. 60-62° C.) upon standing.

Elemental Analysis for: C₁₉H₁₉NO₇S; Calc'd: C, 56.29; H, 4.72; N, 3.45. Found: C, 56.13; H, 4.58; N, 3.44.

INTERMEDIATE 6 {7-Nitro-8-[1-propenyl]-2,3-dihydro-1,4-benzodioxin-2-yl}methyl 4-methylbenzenesulfonate

To a solution of 10.0 g (24.0 mmole) of (R)-[8-allyl-7-nitro-2,3-dihydro-1,4-benzodioxin-2-yl]methyl 4-methylbenzenesulfonate in 700 mL of benzene was added 1.03 g of bis(acetonitrile)dichloropalladium (II) and the mixture was refluxed under nitrogen for 48 hours. The catalyst was then removed by filtration and the filtrate concentrated in vacuum to a brown oil. Column chromatography on silica gel with methylene chloride as eluant gave 7.2 g of the title compound as a mixture of E and Z isomers. A sample of {(2R)-7-nitro-8[(E)-1-propenyl]-2,3-dihydro-1,4-benzo-dioxin-2-yl}methyl 4-methylbenzenesulfonate was obtained as a yellow solid (m.p. 105-106° C.) by evaporation of a pure E isomer-containing fraction.

Elemental Analysis for: C₁₉H₁₉NO₇S; Calc'd: C, 56.29; H, 4.72; N, 3.45. Found: C, 56.12; H, 4.64; N, 3.39.

INTERMEDIATE 7 (8-Formyl-7-nitro-2,3-dihydro-1,4-benzodioxin-2-yl)methyl 4-methylbenzenesulfonate

{(2R)-7-Nitro-8-[1-propenyl]-2,3-dihydro-1,4-benzodioxin-2-yl}methyl 4-methylbenzenesulfonate (10.5 g, 25.9 mmole) dissolved in 400 mL of methylene chloride was treated with excess ozone at −78° C. Diisopropylethylamine (11.5 mL, 66.0 mmole) was then added dropwise over 30 min and the mixture allowed to come to room temperature and stir overnight under a nitrogen atmosphere. The mixture was then diluted to 600 mL with methylene chloride, washed three times with 100 mL portions of 2N HCl (aq), twice with 200 mL portions of saturated aqueous sodium bicarbonate and with 200 mL of saturated brine. The solution was dried over magnesium sulfate, filtered and concentrated in vacuum to a crude brown oil, which was column chromatographed on silica gel with 10% hexane/methylene chloride to give 7.52 g of the (R)-enantiomer of the title compound as a yellow solid. ¹H-NMR (CDCl₃): doublet 7.8 δ (2H); doublet 7.62 δ (1H); doublet 7.4 δ (2H); doublet 7.0 δ (1H); multiplet 4.4-4.6 δ (2H); multiplet 4.2 δ (3H); singlet 2.4 δ (3H).

INTERMEDIATE 8 6-Nitro-3-(toluene-4-sulfonyloxymethyl)-2,3-dihydro-benzo[1,4]dioxin-5-yl) carboxylic acid

The oxidation reagent was prepared by dissolving 7.0 g (70 mmole) of chromium trioxide in 10 mL of water in a 50 mL beaker. The beaker was immersed in an ice bath and 6.1 mL (110 mmoles) of concentrated sulfuric acid added, followed by 20 mL additional water. The oxidant was added dropwise to a solution of (2R)-(8-formyl-7-nitro-2,3-dihydro-1,4-benzodioxin-2-yl)methyl 4-methyl-benzenesulfonate (12.4 g, 30.6 mmole) dissolved in 100 mL of acetone and cooled in an ice bath. The mixture was stirred at room temperature for 3 hours after the addition was complete. Sodium bisulfite was then added in small portions until the brown color was gone. The mixture was diluted to 500 mL with water and extracted twice with 300 mL portions of ethyl acetate. The combined extracts were washed with 300 mL of water and with 300 mL of saturated brine, dried over sodium sulfate, filtered and evaporated to 13.4 g of the (R)-enantiomer of the title compound as a viscous yellow oil. ¹H-NMR (CDCl₃): 2 superimposed doublets 7.8 δ (3H); doublet 7.4 δ (2H); doublet 7.0 δ (1H); multiplet 4.55 δ (1H); doublet 4.45 δ (1H); multiplet 4.25 δ (3H); singlet 2.4 δ (3H).

INTERMEDIATE 9 Toluene-4-sulfonic acid 8-amino-7-nitro-2,3-dihydro-benzo(1,4)dioxin-2-ylmethyl ester

To 7.0 g (17 mmole) of (S)-6-nitro-3-(toluene-4-sulfonyloxymethyl)-2,3-dihydro-benzo[1,4]dioxin-5-yl) carboxylic acid in 250 mL of tetrahydrofuran was added 9.4 g (34 mmole) of diphenylphosphoryl azide and 5.2 g (40 mmole) of diisopropylethylamine and the mixture was refluxed under nitrogen for 24 hours. Water (3 mL) was added and the mixture refluxed under nitrogen overnight. The reaction was diluted to 600 mL with ethyl acetate and washed with 300 mL portions of 1 N HCl, saturated aqueous sodium bicarbonate and saturated brine. The mixture was then dried over sodium sulfate, filtered and concentrated in vacuum and the residue column chromatographed on silica gel with methylene chloride as eluant to give 4.1 g of the (R)-enantiomer of the title compound as a yellow solid (m.p. 155° C.).

Elemental Analysis for: C₁₆H₁₆ N₂O₇S; Calc'd: C, 50.52; H, 4.24; N, 7.36. Found: C, 50.27; H, 3.99; N, 7.23.

INTERMEDIATE 10 [7,8-Diamino-2,3-dihydro-1,4-benzodioxin-2-yl]methyl 4-methylbenzenesulfonate

Toluene-4-sulfonic acid (2R)-8-amino-7-nitro-2,3-dihydro-benzo(1,4)dioxin-2-ylmethyl ester (4.1 g, 11 mmole) was dissolved in 200 mL of methanol to which 0.50 g of 10% palladium on carbon had been added. 4 N isopropanol HCl (10 mL) was then added and the mixture treated with 60 psi of hydrogen on a Parr apparatus overnight. The mixture was filtered through celite and concentrated in vacuum to give 4.6 g of the (R)-enantiomer of the title compound as a pink solid dihydrochloride, (m.p. 178-180° C.).

Elemental Analysis for: C₁₆H₁₈N₂O₅S·2 HCl; Calc'd: C, 45.40; H, 4.76; N, 6.62. Found: C, 45.06; H, 4.63; N, 6.47.

INTERMEDIATE 11 (2-Trifluoromethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalen-8-yl)methyl 4-methylbenzenesulfonate

A solution of 3.1 g (7.3 mmole) of [(2R)-7,8-diamino-2,3-dihydro-1,4-benzodioxin-2-yl]methyl 4-methylbenzenesulfonate dihydrochloride in 50 mL of trifluoroacetic acid was refluxed under nitrogen for 6 hours. The mixture was diluted to 400 mL with methylene chloride, washed with 400 mL of water and with 400 mL of saturated aqueous sodium bicarbonate, dried over magnesium sulfate, filtered and concentrated to a crude foam in vacuum. The crude product was column chromatographed on silica gel with 1% methanol in chloroform and the product fractions combined and concentrated in vacuum to give 3.3 g of the (R)-enantiomer of the title compound as a white solid, m.p. 114-116° C., which retains one equivalent of chloroform.

Elemental Analysis for: C₁₈H₁₅F₃N₂O₅S·CHCl₃; Calc'd: C, 41.66; H, 2.94; N, 5.11. Found: C, 41.74; H, 2.76; N, 5.11.

EXAMPLE 1 8-[4-(5-Fluoro-1H-indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2-trifluoromethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene

A mixture of 0.50 g (1.2 mmole) of [(8R)-2-trifluoromethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalen-8-yl]methyl 4-methylbenzenesulfonate and 1.0 g (4.6 mmole) of 5-fluoro-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole in 5.0 mL of DMSO was heated at 85° C. under nitrogen for 6 hours. The reaction was allowed to come to room temperature, diluted to 250 mL with ethyl acetate, washed with 250 mL portions of saturated aqueous sodium bicarbonate and water, dried over sodium sulfate, filtered and evaporated in vacuum. The residue was column chromatographed on silica gel with 1% methanol in chloroform as eluant and the product fractions concentrated in vacuum to give 0.45 g of the desired compound as the free base. Recrystallization from ethanol with the addition of 0.11 g of fumaric acid gave 0.25 g of the (S)-enantiomer of the title compound as a yellow solid hemifumarate, m.p. 236-238° C.

Elemental Analysis for: C₂₄H₂₀F₄N₄O₂·0.5 C₄H₄O₄; Calc'd: C, 58.87; H, 4.18; N, 10.56. Found: C, 58.64; H, 4.19; N, 10.17.

EXAMPLE 2 8-[4-(1H-Indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2-trifluoromethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene

A mixture of 0.50 g (1.2 mmole) of [(8R)-2-trifluoromethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalen-8-yl]methyl 4-methylbenzenesulfonate and 1.0 g (5.0 mmole) of 3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole in 8.0 mL of DMSO was heated at 85° C. under nitrogen for 6 hours. The reaction was allowed to come to room temperature, diluted to 400 mL with ethyl acetate, washed with 400 mL portions of saturated aqueous sodium bicarbonate, water and saturated brine, dried over sodium sulfate, filtered and evaporated in vacuum. The residue was column chromatographed on silica gel with 1% methanol in chloroform as eluant and the product fractions concentrated in vacuum to give 0.40 g of the desired compound as the free base. Recrystallization from ethanol with the addition of 0.12 g of fumaric acid gave 0.24 g of the (S)-enantiomer of the title compound as a pale yellow solid fumarate, m.p. 231-233° C.

Elemental Analysis for: C₂₄H₂₁F₃N₄O₂·C₄H₄O₄; Calc'd: C, 58.95; H, 4.42; N, 9.82. Found: C, 58.61; H, 4.40; N, 9.81.

EXAMPLE 3 8-[4-(6-Fluoro-1H-indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2-trifluoromethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene

A mixture of 0.50 g (1.2 mmole) of [(8R)-2-trifluoromethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalen-8-yl]methyl 4-methylbenzenesulfonate and 0.90 g (4.2 mmole) of 6-fluoro-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole in 8.0 mL of DMSO was heated at 85° C. under nitrogen for 6 hours. The reaction was allowed to come to room temperature, diluted to 400 mL with ethyl acetate, washed with 400 mL portions of saturated aqueous sodium bicarbonate and water, dried over sodium sulfate, filtered and evaporated in vacuum. The residue was column chromatographed on silica gel with 1% methanol in chloroform as eluant and recrystallized from ethanol with the addition of 0.10 g of fumaric acid to give 0.16 g of the (S)-enantiomer of the title compound as a yellow solid hemifumarate, hydrate, m.p. 215-220° C.

Elemental Analysis for: C₂₄H₂₀F₄N₄O₂·0.5C₄H₄O₄·H₂O; Calc'd: C, 56.94; H, 4.41; N, 10.21. Found: C, 57.02; H, 4.48; N, 10.21.

INTERMEDIATE 12 (2-Methyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalen-8-yl)methylchloride

A solution of 2.3 g (5.4 mmole) of [(2R)-7,8-diamino-2,3-dihydro-1,4-benzodioxin-2-yl]methyl 4-methylbenzenesulfonate dihydrochloride in 50 mL of acetic acid was refluxed under nitrogen for 24 hours. The solvent was removed in vacuum and the residue dissolved in 400 mL of ethyl acetate, washed with 300 mL of water and with 300 mL of saturated aqueous sodium bicarbonate, dried over magnesium sulfate, filtered and concentrated to a crude foam in vacuum. The crude product was column chromatographed on silica gel with 2% methanol in chloroform and the product fractions combined and concentrated in vacuum to give 1.1 g of the (R)-enantiomer of the title compound as a yellow oil. MS (+APCl) m/z 239 (M+H)+.

EXAMPLE 4 8-[4-(1H-Indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2-methyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene

A mixture of 0.50 g (2.1 mmole) of [(8R)-2-methyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalen-8-yl]methyl chloride and 1.0 g (5.0 mmole) of 3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole in 10.0 mL of DMSO was heated at 100-110° C. under nitrogen for 6 hours. The reaction was allowed to come to room temperature, diluted to 500 mL with ethyl acetate, washed with 400 mL portions of saturated aqueous sodium bicarbonate, water and saturated brine, dried over sodium sulfate, filtered and evaporated in vacuum. The residue was column chromatographed on silica gel with 1% methanol in chloroform as eluant and the product fractions concentrated in vacuum to give the desired compound as the free base. Recrystallization from ethanol with the addition of 0.12 g of fumaric acid gave 0.11 g of the (S)-enantiomer of the title compound as a yellow solid fumarate, one-quarter hydrate, m.p. 219-222° C.

Elemental Analysis for: C₂₄H₂₄N₄O₂·C₄H₄O₄·0.25 H₂O; Calc'd: C, 64.54; H, 5.51; N, 10.75. Found: C, 64.28; H, 5.36; N, 10.64.

INTERMEDIATE 13 Toluene-4-sulfonic acid 8-methylamino-7-nitro-2,3-dihydro-benzo(1,4)dioxin-2-ylmethyl ester

To 2.2 g (5.8 mmole) of toluene-4-sulfonic acid (2R)-8-amino-7-nitro-2,3-dihydro-benzo(1,4)dioxin-2-ylmethyl ester in 100 mL of methylene chloride was added 1.3 g (10 mmole) of N,N-diisopropylethylamine, followed by 2.1 g (10 mmole) of trifluoroacetic anhydride. The mixture was stirred at room temperature for 2 hours, then washed with 100 mL portions of 2 N HCl (aq) and water, dried over sodium sulfate, filtered through silica gel, using additional methylene chloride to fully elute the product, and concentrated in vacuum to 2.6 g (5.4 mmole) of the trifluoroacetamide. This was dissolved in 50 mL of N,N-dimethylformamide and 1.2 g (6.5 mmole) of methyl tosylate and 3.0 g (22 mmole) of potassium carbonate added. The mixture was heated at 50-60° C. under nitrogen for 15 hours. After the mixture had cooled, it was diluted to 300 mL with ethyl acetate and washed with 300 mL of water. The aqueous phase was back-extracted with 200 mL of ethyl acetate and the combined organics were washed with 250 mL portions of water and saturated brine, dried over sodium sulfate, filtered and concentrated in vacuum. The residue was dissolved in 300 mL of methanol and 5.0 g (36 mmole) of potassium carbonate added. This mixture was stirred at room temperature for 24 hours, then filtered and concentrated in vacuum. The residue was column chromatographed on silica gel with methylene chloride as eluant to give 0.80 g of the (R)-enantiomer of the title compound as a yellow solid, m.p. 149-151° C.

Elemental Analysis for: C₁₇H₁₈N₂O₇S; Calc'd: C, 51.77; H, 4.60; N, 7.10. Found: C, 51.35; H, 4.40; N, 6.95.

INTERMEDIATE 14 (1,2-Dimethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalen-8-yl)methyl 4-methylbenzenesulfonate

To a mixture of 0.80 g (2.0 mmole) of (2R)-8-methylamino-7-nitro-2,3-dihydro-benzo(1,4)dioxin-2-ylmethyl ester and 250 mg of 10% palladium on carbon in 200 mL of methanol in a 500 mL Parr hydrogenation bottle was added 2.0 mL of 4 N isopropanolic HCl. The mixture was hydrogenated at 50 psi for 15 hours. The mixture was then filtered through celite and concentrated in vacuum. The residue was dissolved in 50 mL of acetic acid and refluxed under nitrogen for 4 hours. After the reaction had cooled, the solvent was removed in vacuum and replaced with 300 mL of methylene chloride. The solution was washed with 300 mL portions of water, saturated aqueous sodium bicarbonate and saturated brine, dried over magnesium sulfate, filtered and concentrated in vacuum. The residue was column chromatographed on silica gel with 0-2% methanol in methylene chloride to give 0.69 g of the (R)-enantiomer of the title compound as a yellow oil, contaminated with the compound in which the tosylate was replaced with chloro. ¹H-NMR (CDCl₃): doublet 7.75 δ (2H); doublet 7.26 δ (2H); doublet 7.10 δ (1H); doublet 6.68 δ (1H); multiplet 4.5 δ (1H); multiplet 4.25 δ (3H); multiplet 4.05 δ (1H); singlet 3.05 δ (3H); singlet 2.5 δ (3H); singlet 2.4 δ (3H).

EXAMPLE 5 8-[4-(1H-Indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-1,2-dimethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene

A mixture of 0.69 g (1.8 mmole) of [(8R)-1,2-dimethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalen-8-yl]methyl 4-methylbenzenesulfonate and 1.0 g (5.0 mmole) of 3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole in 10.0 mL of DMSO was heated at 90-100° C. under nitrogen for 6 hours. The reaction was allowed to come to room temperature, diluted to 500 mL with ethyl acetate, washed with 400 mL portions of saturated aqueous sodium bicarbonate, water and saturated brine, dried over sodium sulfate, filtered and evaporated in vacuum. The residue was column chromatographed on silica gel with 0-3% methanol in chloroform as eluant and the product fractions concentrated in vacuum to give 0.090 g of the desired compound as the free base. Recrystallization from ethanol with the addition of 0.025 g of fumaric acid gave the (S)-enantiomer of the title compound as a yellow solid, m.p. 186-188° C.

Elemental Analysis for: C₂₅H₂₆N₄O₂·C₄H₄O₄·0.25 H₂O; Calc'd: C, 65.10; H, 5.75; N, 10.47. Found: C, 64.97; H, 5.71; N, 10.33.

INTERMEDIATE 15 (2-Ethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalen-8-yl)methyl 4-methylbenzenesulfonate

Toluene-4-sulfonic acid (2R)-8-amino-7-nitro-2,3-dihydro-benzo(1,4)dioxin-2-yl-methyl ester (1.0 g, 2.6 mmole) was dissolved in 100 mL of methanol to which 0.25 g of 10% palladium on carbon had been added. p-Toluenesulfonic acid (1.0 g, 5.2 mmole) was then added and the mixture treated with 60 psi of hydrogen on a Parr apparatus for 15 hours. The mixture was filtered through celite and concentrated in vacuum. Propionic acid (50 mL) was added and the solution refluxed under nitrogen for 4 hours. The solvent was removed in vacuum and the residue dissolved in 300 mL of methylene chloride, washed with 200 mL each of saturated aqueous sodium bicarbonate, water and saturated brine, dried over magnesium sulfate, filtered and concentrated in vacuum to give 0.84 g of the (R)-enantiomer of the title compound as a white foam. ¹H-NMR (CDCl₃): doublet 7.8 δ (2H); doublet 7.3 δ (2H); doublet 7.0 δ (1H); doublet 6.75 δ (1H); multiplet 4.5 δ (1H); multiplet 4.25 δ (3H); multiplet 4.05δ (1H); quartet 2.9 δ (2H); singlet 2.45 δ (3H); triplet 1.4 δ (3H).

EXAMPLE 6 8-[4-(1H-Indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2-ethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene

A mixture of 0.84 g (2.2 mmole) of [(8R)-2-ethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalen-8-yl]methyl 4-methylbenzenesulfonate and 1.5 g (7.60 mmole) of 3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole in 10.0 mL of DMSO was heated at 80° C. under nitrogen for 6 hours. The reaction was allowed to come to room temperature, diluted to 500 mL with ethyl acetate, washed with 400 mL portions of saturated aqueous sodium bicarbonate, water and saturated brine, dried over sodium sulfate, filtered and evaporated in vacuum. The residue was column chromatographed on silica gel with 0-3% methanol in chloroform as eluant and the product fractions concentrated in vacuum to give 0.53 g of the desired compound as the free base. Recrystallization from ethanol with the addition of one equivalent of fumaric acid gave 0.46 g of the (S)-enantiomer of the title compound as a pale yellow solid fumarate, m.p. 231-232° C.

Elemental Analysis for: C₂₅H₂₆N₄O₂·C₄H₄O₄; Calc'd: C, 65.65; H, 5.70; N, 10.56. Found: C, 65.61; H, 5.73; N, 10.36.

EXAMPLE 7 8-[4-(7-Fluoro-1H-indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2-trifluoromethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene

A mixture of 1.0 g (2.4 mmole) of [(8R)-2-trifluoromethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalen-8-yl]methyl 4-methylbenzenesulfonate and 1.8 g (8.4 mmole) of 7-fluoro-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole in 15 mL of DMSO was heated at 80° C. under nitrogen for 6 hours. The reaction was allowed to come to room temperature, diluted to 400 mL with ethyl acetate, washed with 400 mL portions of saturated aqueous sodium bicarbonate and water, dried over sodium sulfate, filtered and evaporated in vacuum. The residue was column chromatographed on silica gel with 1% methanol in chloroform as eluant and recrystallized from ethanol with the addition of 0.20 g of fumaric acid to give 0.64 g of the (S)-enantiomer of the title compound as a white solid fumarate, m.p. 239-240° C.

Elemental Analysis for: C₂₄H₂₀F₄N₄O₂·C₄H₄O₄; Calc'd: C, 57.15; H, 4.11; N, 9.52. Found: C, 57.10; H, 4.05; N, 9.39.

INTERMEDIATE 16 (2-Pentafluoroethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalen-8-yl)methyl 4-methylbenzenesulfonate

A solution of 1.0 g (2.4 mmole) of [(2R)-7,8-diamino-2,3-dihydro-1,4-benzodioxin-2-yl]methyl 4-methylbenzenesulfonate dihydrochloride in 30 mL of pentafluoropropionic acid was refluxed under nitrogen for 6 hours. The mixture was diluted to 400 mL with methylene chloride, washed with 400 mL of water and with 400 mL of saturated aqueous sodium bicarbonate, dried over magnesium sulfate, filtered and concentrated to a crude foam in vacuum. The crude product was column chromatographed on silica gel with 1% methanol in chloroform and the product fractions combined and concentrated in vacuum to give 0.90 g of the (R)-enantiomer of the title compound as a yellow oil. ¹H-NMR (CDCl₃): doublet 7.75 δ (2 H); doublet 7.3 δ (2H); doublet 7.15 δ (1H); doublet 6.9 δ (1H); multiplet 4.5 δ (1H); doublet of doublets 4.25 δ (1H); multiplet 4.2 δ (2H); doublet of doublets 4.1 δ (1 H); singlet 2.4 δ (3H).

EXAMPLE 8 8-[4-(1H-Indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2-pentafluoroethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalene

A mixture of 0.90 g (1.9 mmole) of [(8R)-2-pentafluoroethyl-7,8-dihydro-3H-6,9-dioxa-1,3-diaza-cyclopenta[a]naphthalen-8-yl]methyl 4-methylbenzenesulfonate and 1.6 g (8.0 mmole) of 3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole in 20 mL of DMSO was heated at 80° C. under nitrogen for 6 hours. The reaction was allowed to come to room temperature, diluted to 400 mL with ethyl acetate, washed with 400 mL portions of saturated aqueous sodium bicarbonate and water, dried over sodium sulfate, filtered and evaporated in vacuum. The residue was column chromatographed on silica gel with 1% methanol in chloroform as eluant and the product fractions concentrated in vacuum and recrystallized from ethanol with the addition of 0.20 g of fumaric acid to give 0.39 g of the (S)-enantiomer of the title compound as a white solid fumarate, m.p. 238-239° C.

Elemental Analysis for: C₂₅H₂₁F₅N₄O₂·C₄H₄O₄; Calc'd: C, 56.13; H, 4.06; N, 9.03. Found: C, 56.10; H, 4.04; N, 8.92. 

1. A method of treating a subject suffering from a condition selected from the group consisting of post-traumatic stress disorder, premenstrual dysphoric disorder, attention deficit disorder, obesity, eating disorders, vasomotor flushing, cocaine and alcohol addiction, and sexual dysfunction, which comprises providing to the subject suffering from said condition, a therapeutically effective amount of a compound of formula I

wherein R¹, R², R³, R⁴, R⁵ and R⁸ are independently hydrogen, halo, cyano, carboxamido, carboalkoxy of two to six carbon atoms, trifluoromethyl, pentafluoroethyl, alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 6 carbon atoms, alkanoyloxy of 2 to 6 carbon atoms, amino, mono- or di-alkylamino in which each alkyl group has 1 to 6 carbon atoms, alkanamido of 2 to 6 carbon atoms, or alkanesulfonamido of 1 to 6 carbon atoms; R⁶ and R⁷ are, independently, hydrogen or alkyl of 1 to 6 carbon atoms; A dotted line represents an optional double bond; Z is CR⁸ or N; and n is an integer 0, 1 or 2; or a pharmaceutically acceptable salt thereof.
 2. The method of claim 1 wherein the subject is a human. 